Thin-film magnetic recording heads have gained wide acceptance in the data storage industry. Due to their small size, thin-film magnetic heads form narrow tracks of data on to the magnetic media of magnetic memory devices, such as computer hard disks, and digital data tape drives. These narrow data tracks allow the device to store more data tracks per area of media and therefore more data per device. Accordingly, reducing the size of the recording head results in an increase in the total data storage capacity of a magnetic memory device.
Typically, a thin-film magnetic head is formed from a substrate that includes a pole-tip assembly that comprises two conductive layers, called poles, separated at one end by an insulating layer and conductively connected at the opposite end to form a single magnetic device capable of generating and detecting magnetic fields. The size of the pole-tip assembly, which includes features on the order of one-half a micron, in part determines the magnetic field pattern produced by the pole-tip assembly. This magnetic field pattern effects how narrowly the recording head can record data tracks. Accordingly, manufacturers seek to form the geometry of the pole-tip assembly as precisely as possible to thereby achieve pole-tip assemblies capable of providing magnetic field patterns suitable for reading and writing narrow tracks of recorded data.
Manufacturers presently attempt to form the precise footprint of the pole-tip assembly by employing lithographic techniques to fabricate the read/write heads. Typically, the lithographic technique deposits alternating layers of conductive and insulating materials onto the substrate by means of an evaporation, sputtering, plating, or other deposition technique that provides precise control of the deposition thicknesses. In a subsequent step, the technique employs chemical etching, reactive ion etching (RIE), or other means to shape and form the deposited layers into a pole-tip assembly having the desired geometry.
Although the existing lithographic techniques work sufficiently well to provide pole-tip assemblies having feature sizes suitable for today's data storage capacity, these lithographic techniques are quickly reaching their limit as to the feature sizes that can be produced. For example, the present photolithographic techniques require precise application of photoresist layers to the surface of the pole assembly. Commonly, the photoresist layer is applied with a topology that includes voids having 10:1 aspect ratios. Such photoresist topologies are difficult to achieve reliably and consequently, manufacturing defects are common.
Moreover, these lithographic techniques are poorly suited for large scale manufacturing. Specifically, lithographic etching of pole-tip assemblies is time consuming and material intensive. Further, the purpose of the lithographic etching of pole-tip assemblies is to correct manufacturing defects that occurred during the manufacture of the pole-tip assembly. However, the defective geometries that occur during the manufacturing process are difficult to predict and prone to wide variations. Accordingly, the application of a universal photoresist pattern to the surface of a pole-tip assembly is a generalized solution that often is ill suited to the actual manufacturing defect of a subject read/write head. Therefore, current techniques for producing a magnetic recording head have several serious limitations with respect to their ability to control the physical geometry of the recording head. Consequently, current techniques are unacceptable for purposes of accurately shaping the recording heads for use in the higher density data storage devices desired by today's computer users.
Accordingly, it is an object of the present invention to provide improved manufacturing processes for manufacturing thin-film magnetic read/write heads, and more particularly, for precisely forming the pole-tip assembly of a magnetic read/write head.
It is a further object of the present invention to provide processes for manufacturing read/write heads that reduce the quantity of chemicals employed during the manufacturing processes.
It is a further object of the present invention to provide manufacturing processes more facile at adapting the geometry of a pole-tip assembly.
It is yet another object of the present invention to provide magnetic thin-film heads with pole-tip assemblies that include contoured surfaces.
It is still another object of the present invention to provide processes for manufacturing read/write heads that provide improved quality control.
The invention will next be described in connection with certain embodiments; however, it will be clear to those skilled in the art of semiconductor device fabrication that various modifications, additions and subtractions can be made to the below-described embodiments without departing from the spirit or scope of the invention.